• Title/Summary/Keyword: marine biofilm

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Purification and Characterization of Biosurfactant from Bacillus sp. DYL130 (Bacillus sp. DYL130 균주의 Biosurfactant의 정제 및 특성)

  • Park, In-Hye;Kim, Sun-Hee;Lee, Sang-Cheol;Ha, Soon-Ok;Lee, Yong-Seok;Ryu, Ah-Reum;Kim, Keun-Ki;Choi, Yong-Lark
    • Journal of Marine Bioscience and Biotechnology
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    • v.1 no.4
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    • pp.268-274
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    • 2006
  • Bacillus sp. DYL130 producing biosurfactant was isolated from soil samples in the Duck-yu mountain and identified as Bacillus sp. by analysis of 16S rDNA sequence. Purification of the biosurfactant was performed by using affinity chromatography and TLC. The biosurfactant of culture medium from Bacillus sp. DYL130 was eluted with 100% methanol using affinity chromatography. To remove methanol, a rotary evaporator was used and enrichment sample was dissolved in alkaline water(pH 10). The purified biosurfactant was identified by TLC. It was confirmed that the Rf value of the biosurfactant was 0.78. Antifungal activity against Botrytis cineria was showed the strongly activity as active antagonist. Maximum emulsification activity and stability were obtained from soybean oil. The critical micelle concentration (CMC) of purified biosurfactant was 35mg/l and the purified biosurfactant inhibited biofilm forming by Bacillus sp..

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Homology Modeling and Characterization of Oligoalginate Lyase from the Alginolytic Marine Bacterium Sphingomonas sp. Strain MJ-3 (알긴산을 분해하는 해양미생물인 Sphingomonas sp. MJ-3 균주의 올리고알긴산 분해효소의 상동성 모델링 및 특성연구)

  • Kim, Hee Sook
    • Journal of Life Science
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    • v.25 no.2
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    • pp.121-129
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    • 2015
  • Alginates are found in marine brown seaweeds and in extracellular biofilms secreted by some bacteria. Previously, we reported an oligoalginate lyase from Sphingomonas sp. MJ-3 (MJ3-Oal) that had an exolytic activity and protein sequence homology with endolytic polymannuronate (polyM) lyase in the N-terminal region. In this study, the MJ3-Oal was tested for both exolytic and endolytic activity by homology modeling using the crystal structure of Alg17c from Saccharophagus degradans 2-40T. The tyrosine residue at the $426^{th}$ position, which possibly formed a hydrogen bond with the substrate, was mutated to phenylalanine. The FPLC profiles showed that MJ3-Oal degraded alginate quickly to monomers as a final product through the oligmers, whereas the Tyr426Phe mutant showed only exolytic alginate lyase activity. $^1H$-NMR spectra also showed that MJ3-Oal degraded the endoglycosidic bond of polyM and polyMG (polymannuronate-guluronate) blocks. These results indicate that oligoalginate lyase from Sphingomonas sp. MJ-3 probably catalyzes the degradation of both exo- and endo-glycosidic bonds of alginate.